An alternating-current surface-discharging panel representative of plasma display panels (hereinafter abbreviated as “panels”) has a large number of discharge cells formed between the front plate and the rear plate faced with each other.
For the front plate, a plurality of display electrode pairs, each made of a scan electrode and a sustain electrode, are formed on a front glass substrate in parallel with each other. A dielectric layer and a protective layer are formed to cover these display electrode pairs.
For the rear plate, a plurality of parallel data electrodes are formed on a rear glass substrate and a dielectric layer is formed over the data electrodes to cover them. Further, a plurality of barrier ribs are formed on the dielectric layer in parallel with the data electrodes. Phosphor layers are formed over the surface of the dielectric layer and the side faces of the barrier ribs. Then, the front plate and the rear plate are faced with each other and sealed together so that the display electrode pairs are intersected with data electrodes. A discharge gas is charged into an inside discharge space formed between the plates. Discharge cells are formed in portions where the respective display electrode pairs are faced with the corresponding data electrodes.
In a panel structured as above, gas discharge generates ultraviolet light in each discharge cell. This ultraviolet light excites the phosphors of red (R), green (G), and blue (G) so that they emit the respective colors for color display.
A general method of driving a panel is a sub-field method; one field period is divided into a plurality of sub-fields and combinations of light-emitting sub-fields provide gradation display.
Each sub-field has a setup period, an address period, and a sustain period. In the setup period, initializing discharge is generated to form wall charge necessary for the succeeding address operation on the respective electrodes. In the address period, address discharge is generated selectively in the discharge cells used to display an image, to form wall charge. Then, alternately applying sustaining pulses to the display electrode pairs each made of a scan electrode and a sustain electrode generates sustain discharge in the discharge cells having generated address discharge therein, and causes the phosphor layers of the corresponding discharge cells to emit light. Thus, an image is displayed.
It is also known that discharge characteristics change, depending on the temperature of the discharge cells in such a panel. For this reason, in a plasma display device for displaying images using such a panel, the brightness of images displayed on the panel and the drive margin during driving the panel change, depending on the panel temperature.
Proposed to address such a problem are methods of detecting the temperature of the panel, and making various kinds of corrections according to the detected temperature so that the influence of the temperature on the panel does not degrade the quality of the images displayed on the panel.
For example, Patent Document 1 discloses a plasma display device including a panel temperature detector for detecting the temperature of the panel in which the writing pulse cycles are changed according to the temperature information from the panel temperature detector.
However, because the temperature distribution of the panel is not uniform in some areas of the panel, the entire display areas are not at an equal temperature. Additionally, because the temperature of the panel significantly varies with the images displayed, accurate detection of the panel throughout the panel is difficult. For these reasons, even with correction based on the temperature of the panel detected by the panel temperature detector, optimal driving of the panel is difficult.
To address these problems, the present invention provides a panel driving method and a plasma display panel device in which the highest temperature and the lowest temperature the panel can have are estimated according to the temperature detected by a thermal sensor and the driving mode selected at power-off. Then, the panel is driven according to the estimated highest temperature or the estimated lowest temperature to improve the display quality of the images.
[Patent Document 1]
    Japanese Patent Unexamined Publication No. 2004-61702